Unloader and starter for compressors and pumps.



E. PRIEDRIGHS. UNLOADIIR AND STARTER FOR GOMPRESSORS AND PUMPS.

APPLICATION FILED DEO. 7I 1910.

Patented Sept. 23, 1913.

2 SHEETS-SHEET l.

au Il c E. FRIEDRIGHS.

UNLOADBR AND STARTER FOR GOMPRESSORS AND PUMPS.

APPLICATION FILED DEO.7, 1910.

1,073,801. Patented sept. 23, 1913.

2 SHEETS-SHEB'I' 2.

, jkefc/e Zoff ERNST FRIEDRICHS, 0F BABMEN, GERMANY.

UNLOAZDER AND STARTER (FOB COMPRESSORS AND PUMPS.

sp'fecication of Letters Patent.

Patented Sept. 23, 1913.

Application iled December 7, 1910. Serial No. 596,037.

To all whom t may concern."

Be it known that I, ERNST FRIEDRIcus, `a subject of thc King of Prussia and German Emperor, and a resident of 8 Gre-v luarkerstrasse, Barmen, Germany, have invented new and useful Improvements in Unloaders and Starters for Compressors and Pumps, of which the following .is a specification, reference being had therein to the accompanying drawings.

This invention has reference to a selfacting starting device for .the driving mechanism of compressors and pumps under pressure, and it ispart-icularly intended to avoid having the motor for the operation of the compressor or pump starting under loadA at any time, the motor engine being on the contrary only connected to the compressor, after it has reached its normal number of revolutions.

The arrangement, herein described, can be used both for the well known starters of electroniotor engines as well' as for Specially constructed starters of electric operating machines, and it can also beused advanta-- geously for belt driving.

Aside from the purpose indicated, the subject matter of the invention presents the additional advantage, that the starting de! vicel can be actuated even in the case of any leakages in the compressed air conduit by the combination with additional safety devices and without irregularities.

The invent-ion is shown in several embodiments on the accompanying drawing, in which- Figure l is the starting, device for compressors, driven by electric motors, and at the moment of cutting the motor out of circuit; Fig. 2 shows thesame device with the motor switched into circuit again. Fig. 3 shows diagrammatically the wiring of circuit connections, corresponding to the arrangementof Figs. `l and 2. Fig. 4 is a vertical section through another modification, suitable for ordinary electric starters. Fig. 5 is a section through another modif cation, suitable for compressors with belt driving.

The essential feature of the invention resides in the fact, that by means of the pressure governorwhich is mounted in the compressor conduit, the switch Vfor the motor engine is operated either directly or indirectly and at the same time the arrangement is' such, that the air conduit for the compresser suction pipe is opened, only after the starter haspasselthe last contact. This contact causes the load to be taken off from the conduit leading to the starting valve of the compressor by means of a solenoid or the like,` and by means of a valve, a multiple way cock or some similar controlling device arranged in the operating conduit so that the said starting valve is connected to theatmosphere, and the load is therefore put on the motor.

In the embodiment of the invention, shown in Figs. 1-3, the switching into circuit of the motor starter is effected by a mercury reversible switch t (Fig. 3 and the movement of the motor starter is e Vected by a special auxiliary starter in the well known manner, when the switch arm 0 has reached the last switching contact, so that the number of revolutions of the motor which operates the compressor, is normal, another additional contact which does not interfere with the further movement of the motor engine, is operated, by means of which current, is fed to the solenoid 7:, included in a shunt of the main circuit, and the core of which actuates a controlling slide e, c1 for the conduit g which leads to the starting valve of the compressor, and by this means the compressed air from below .the valve z' is free to escape by way of the said valve e, e1, and the pressure governor Then, the compressor will be able to suck in another supply of fresh air and thereby, it puts the load on the electric motor which is already running at its full capacity. j

In Fig. l of the drawing, b is the pressure governor, a is the corresponding controllin piston the piston rod of which is connecte to the main Contact. The conduit c of the pressure governor is connected to the conduit from which the air is taken oil for consumption. By means of the counter conduit l the pressure governor b is connected to a double auxiliary., slide valve 'f the slide e, el of which connects the conduit g which leads to the compressor starting valve or to its main piston h, alternately withthe auxiliary conduits l and Z, the connection with the conduit d being effected, when there is a minimum of pressure in the working conduit c, while the Aconnection with the conduit Z is effected at an increase of pressure in the the auxiliary valve f,

working conduit up to the adjustable maximum of pressure. v

The mode of operation is as follows: `When the pressure in the conduit has risen up to the admissible maximum of pressure, this causes the piston a of the pressure governorl) to be raised to its highest position (Fig. l). By means of the rod system, connected to the piston ""a, the main switch t of the electric motor operating the pump, is reversed, the motor being thereby arrested. rIhen the air pressure from the conduit c is admitted below the piston a, by means of the conduit d, and through the conduit d it passes below the part e1 of the slide e, e1 of and through the annular space e2 of the slide e, e1, it is admitted into the conduit g and below the piston h of the compressor suction valve z'. The com-- pressor will then run idle. By the reversing of the main switch t for the electric motor however, the solenoid la which operates the slide e, e1 is ,denergized and allows the slide e, e1 to drop (position shown in full lines in Fig. 1). In this position of the slide e, c1 the compressed air under its full pressure iows through the conduit l and through the annular space e2 of the slide e, e1 and through the conduit g' below the piston L of the compressor suction valve z-, and

` thereby lmaintains this valve in the raised position. InA consequence thereof both the action of 'motor as well as the compressor is arrested. Inasmuch as the compressor has now ceased .to work and does not produce any new quantities of compressedr air,fthe pressure in the conduit c will have gone down to the minimum in a short time by the consumption of compressed air. In consequence of this minimum however, the piston a descends,` and it iinall assumes the position, shown in Fig. 2 of t e drawing, so that the air would escape to the outside from theconduit d, and would release the suction valvescausing them to operate, were it not for the presence of the auxiliary valve j' which keeps the air conduit g, d still closed,

as the slide e, e? still maintains its position indicated in full lines in Fig. 1 of the drawing. In this lower position of the governor piston a the main switch is again in the operating position, so that the electric motor begins to move, thou-gh the suction valve z' is still prevented from operating, in view of the fact, that the slide e, el as indicated above, is still maintained 1n its lower position (shown in Fig. 1). Only ai" er the starter has reached the last contact, the aux- -the conduits g, and

iliary contact (tp in Fig. 3) for the solenoid c of the valve f is closed, the solenoid 7c is energized, and the slide valve e, el is raised, so that the pressure under the piston h disappears in consequencev of the connection of al with the outside. The suction valve z' is thereby caused to drop governor is also lowered, and assumes back upon its seat and air can be sucked in again `through the tubing o from the outside.

The mode of operation of the modification, shown in Fig. Llis as follows: The piston o contained in the pressure governor la is forced into its highest position, when the pressure is at its maximum by the compressed air, admitted from the air pressure conduit through the pipe 70. When the air pressure is reduced by the consumption of air below a certain limit, for which the pressure governor can be adjusted by the sliding weight q, the piston the lower position, indicated in Fig. 5. In this position ofthe piston vo1 the connecting pipe g, h and in consequence thereof that part of the interior of the cylinder b below the piston u are connected to the outside air, and both pistons d and u, are depressed into their lower positions d1 and u1 by the air pressure acting upon the piston d. By means of the rack bar r'whichconstitutes the middle of the piston rod c and by the `toothed wheel s engaging with the lrack bar,

the rectilinear vmovement of the two pistons d and u is converted into a rotating movement. By mea-ns of a sprocket wheel or a rope pulley or sheave t mounted on the shaft ofthe toothed wheel, the rotary movement is then transmitted to the motor starter L, as shown in Fig. 4 or to a belt shifter F, shown in Fig. '5.

In the mode of operation, herein described the compressor would be operated, andthe feeding of air to the receiver would commence, but for the auxiliary valve f which in the position which its slide valve e, el assumes in Fig. 4 of the drawing, retains the compressed air in the connecting pipe 111, so as to act below the piston lw, and locks the blow off valve m in its highest position. Only after the rack bar 1- has moved the two-armed lever 2 and consequently the piston e, e1 of the auxiliary valve f to its upper position, indicated in Fig. 5 of the drawing by means of the guide block y connected to the arm of the piston rod c which is eected shortly before the rack barv v' has reached its lowest position, the air,l

inclosed below the piston fw of the blow off valve m, is free to escape through the pipes fv,`g. and z. and by way of the pressure governor Ze, and by way of the piston which is then in its position, indicated at 0JL in Fig. 5 of the drawing, the air escaping to the outside, while the piston w, and the blow olf valve m are lowered into their positions m1 and 'wl1 shown in Fig. 5; the air from the compressor is thereby cut o' vfrom the outside air, and is compelled to flow into the compressed air working conduit N. Hence the compressor is now under load. As soon as the desired maximum of pressure has o of the pressure` lill raised in its upper osition.

been reached,'the piston o of the pressure governor la is raised into its upper position, indicated in Fig. 4 of the drawing; the compressed air passes through the connecting pipe h, and by way of the piston e, e1 which is in its raised position and operates the auxiliary valve f, and through the pipe rv, below the piston w of the blow off valve m, so that these two pistons are raised, and the load is taken voil' the compressor, while the air from the compressor is now free to escape9 to the outside through the blow off valve m which is now opened. At the same time, compressed air passes through the connecting pipe g under the piston u1 which is shown in Fig. 5 in its depressed position.

In the case of equal air pressures acting,

" free section of which lhas been reduced by adjustment of the flat springs al, so that the lmotion of the piston B, and the adjust- Iment of the starter and of the motor are fretarded. When the piston B is moving upward, the oil raises the flat spi'in s D, i and flows through the holes c into the ower ,space of the cylinder E, and cuts out the starter and the motor with a quick motion.

upon the two pistons u, u1 in opposite directions, the lower piston u1 on account of its greater surface will overcome the total pressure of the piston d, and both pistons will be moved into their upper positions d and u indicated-in Fig. 4 of the drawing. rIhis movementis transmitted to the motor starter L of Fig. 4, or to the belt shifter F of Fig. 5 of the drawing in the manner above described by means of the piston rod 1s shown in connection with a belt shifter c, the rack bar 1', the toothed wheel s and the sprocket wheel or the sheave or pulley t, g

i is the pulley of double Width, and mounted upon the driving shaft, H is the loose pulley upon the shaft of the driven compressoi', J is the fast pulley. The operation of i the belt shifter or shipper lever F is effecte ed by means of chains, ropes or by a system 160 -of levers from the sheave or the sprocket the motor and the compressor being stopped in the latter case. In consequence of the movement just described, however, the arm w which is secured to the rack bar r and the guide block yfare moved upward until the guide block, shortly before it has reached its upper position, indicated in Fig. 4 moves the slide valve e, e1 of the auxiliary valve f by means of the two-armed lever s into the lower position, shown in Fig. 4 of the drawing. By means of this position of the auX- iliary valve slide e, `e1 the compressed air under the piston w of the blow off valve m is prevented from returning through the pipe U1 and through the blow 0H valve m in its open position.

In order to avoidv too rapid, premature dropping down of the blew od valve m upon its seat by any possible leakages of the pipe 'v1 or ofits screw threaded fittings, or by I claim-as new, is: auxiliary valve f and of the piston 'w of any leakages of the slide valve e, e1 of the the blow oii' Valve m, and in order to avoid any consequent danger of the starting of the compressor under load, provision ismade, that ycoifnpressed air is always made to pass through the pipe c' and through the slide c, e1 of the auxiliary valve f in its lowest position and through the pipe 'v so that the air gets under `the piston w of the blow ofi:` `valve m, and the valve m is maintained In Fig. 4 the' sel acting'v device is shown in connection with a starter L for an electro motor, driving the compressor.

In order to adapt the herein described vvided with a piston rod A, on which is lower side of the 1 moves in the cylin er/E which is filled with cil, together with the pistons d and u and their common piston rod c, and in the same direction, in such a manner that upon the descent of the piston B, that is to say of the i starter of the motor engine the oil is forced `starting device to the usual rule, observed in the starting of electro motor engines, that is to say, switch in slowly, cut out quickly, the lower extension of the rack bar 1l is promounted the piston B of any well known 7o cushioning or braking device. The piston i B is provided with holes C which are covered up by adjustable flat springs D on the iston B. The piston B ,s

out through the holes C of the piston B the In Fig. 5 the self acting starting device or shipper lever. F is the belt shifter, G

wheel t.

The regulation of the velocity of the shifting movement is effected both by a suitable ratio of the surfaces of the two pistons d A and u as well as by regulating the admission i and the discharge of air by the adjustable P cock K which depends upon the difference i of capacity of the cylinders a and b.

In the case of heavy machinery the air for the regulation of the velocity is replaced :by oil which is introduced into the space between the pistons d and u.

Having now described my invention what 1. In an apparatus of the class described, the combination of a conduit connected with the compressor, a valve in the conduit, a piston. and cylinder device connected with the valve for opening and closing the saine,

a pressure governor connected with the discharge side of the compressor, and an auxiliary valve for connecting the pressureresponsive device to the atmosphere when the pressure on the governor is at a predetermined minimum and for connecting the said device with the discharge side of the compressor when the pressure acting en the pressure governor is above a predetermined maximum.

2. In an apparatus of the class described, the combination of a conduitconnected with the compressor, an unloading valve for opening the conduit to the atmosphere, a pressure-responsive device Vfor controlling the valve, a pipe leading to the said' device, an auxiliary valve connected with the pipe, a pressure governor, a connection between the discharge side of the compressor and the governor and the auxiliary valve whereby 'the output pressure of the compressor acts on the governor and through ton, a connection between thecylinder and said pressure-responsive device, a conduit connected with the dischar e side of the compressor and the said cylindervand controlled by one head of the piston, a pressure governor also connected with the discharge` side of the compressor and including a. movable element, and a connection between the pressure 'governor and said cylinder, said connection being controlled by the movable element of the pressure governoru and by the other head of -the piston of the auxiliary valve.

4. The combination of a cylinder and a double-headed4 piston,

' a connection between the cylinder and said Adevice and cont-rolled by one head of the piston, a conduit connected with the discharge slde of the compressor and connected withv the cylinder and controlled by thel 'same head of the piston that controls the said connection, a pressure governor in` cluding a piston and cylinder, a connection between the pressure governor cylinder and the discharge side of the compressor, anda connection between the auxiliary valve cylinder and the pressure governor cylinder and controlled by the other head of the said piston and also by the piston of the pressure governor whereby the pressure on the, pressure-responsive deviceunay escape through the' auxiliary valve and said last-mentioned connection when the pressure on the governor is below a predetermined minimum.

5. The v combination of an unloading valve, a pressure-responsive device connected therewith, an auxiliary valve consisting of a cylinder and adouble-headed piston, av

connection between the cylinder and said device and vcontrolled by one head ofthe piston,

of anunloading valve, a pressure-responsive device connected therewlth, an auxiliary valve consisting` a conduit connectedfwith the discharge side of the compressor and connected with the cylinder and controlled by the same head of the piston that controls the said connection, a pressure governor including a piston and cylinder, a connection between the pressure governor cylinder and the discharge side of the compressor, a connection between t-he auxiliary valve cylinder and the pressure governor cylinder and controlled by the other head of the said piston and also bythe piston of the pressure governor whereby the pressure on the pressure-responsive device may escape through the auxiliary valve and said last-mentioned connection when the pressure on the governor is below va predetermined minimum, and auxiliaryy valve-actuating means controlled by thel pressure governor and the pressure on the discharge side of the compressorq 6. The combination oi;'. an unloading valve, al pressure-responsivedevice connected therewith, an auxiliaryI valve consistingof a cylinder and-a doubleg-Iheaded piston, a connection between the cylinder and said 4 device and controlled by one head of the piston, a conduit connected with the discharge side of the compressor and connected with the cylinder and controlled by the same head of the piston that controls the said connection, a `pressure governor 1ncluding a piston and cylinder, a connection between the pressure governor cylinder and the discharge side of the compressor, a connection between the auxiliary valve cylinj' der and the pressure governor cylinder and controlledv by the other head of the said piston and also b'y the piston of the pressure governor whereby the pressure on the pressure-responsiv device may escape through the auxiliary valve and sald lastmentioned connection when the pressure on. the governor is below a predetermined minimum, a reci rocatory element for actuatlng the auxiliary valve, and a diierential piston motor connected with the said element having its portion of smaller area connected with the discharge side of the compressor and its portion of larger area connected with the said connection between thel pressure governor and auxiliary valve. l

7. rlhe combination of an unloading valve, a pressure-responsive device'connected therewith, an auxiliary valve consisting of a cylinder and a double-headed piston, a connection between the cylinder and said device and controlled by oIe head of the piston, 4a conduit connected with the discharge side of the compressor and connected with the cylinder and controlled by the same head of the piston that controls'the said connection, va pressure governor including a piston and cylinder, av connection between the pressuregovernor cylinder and the discharge side of the compressor, a connection between the auxiliary valve cylinder and the pressure governor cylinder and controlled by the other head of the said piston and'also by the piston of the pressure governor whereby the pressure on the pressureresponsive device may escape through the auxiliary valve and said last-mentioned connection when the pressurev on the governor isbelow a predetermined minimum, a reciprocatory element for actuating the auX- illary valve, a diii'erential piston motor connected with the said element having its portion of smaller area connected with the dis charge side of the compressor and its portion of larger area connected with the said connection between the pressure governor and auxiliary valve, a motor starter connected with the reciprocatory element, and means for retarding the movement of the element in one direction only.

8. The combination of an unloading valve for a compressor7 a pressure governor connected with the discharge side of the compressor, a pressure-responsive device controlling the said valve,y an auxiliary valve between the pressure governor and pressure-responsive device for controlling the latter, a reciprocatory element, a connection between the said element and auxiliary valve for actuating the latter, and a pneumatic motor having a differential area piston connected with the said element, a connection between the pressure governor and side of the piston of larger area, and a connection between the discharge side of the compressor and the side of the piston of smaller area, and a motor starter operated by the said element- In testimony whereof I afiix my signature in presence of two Witnesses.

ERNST FRIEDRICHS. [11. s]

lVitnesses:

WALTER VONNEGUT, ALFRED HENKEL. 

